The transport of card webs for the production of nonwovens proceeds from the carding machine, in which the card web of material fibers is produced, to the crosslapper, in which several layers of the card web are laid to form a thicker nonwoven. Over the entire transport distance of the card web from the carding machine to the point where the card web is laid in the crosslapper, the problem occurs that the conveyor belts for the card web, because of their high speed, carry along entrained air. When the card web is deflected around deflection rollers or when two conveyor belts are brought together, this air leads to the formation of a bubble. The air escapes laterally and causes the belts to flutter and the card web to be blown about. It can also lead to breaks in the card web and to stretchings or expansions of the card web. Generally, one can say that this air leads to inhomogeneities in the card web. When the card web is deflected around deflection rollers, the centrifugal forces which develop lead additionally to a lengthening of the card web, which also brings with it the danger of the formation of “bags” or folds.
It is known from EP 1 367 166 B1 that, to get rid of the entrained air in a section of the transport path where the card web undergoes a change of direction, a specifically configured guide element can be arranged. The known guide element has a surface which is curved to conform to the course of the transport path. A plurality of radial through-openings is formed in the guide element, and the entrained air is discharged radially through these openings. All of the configurations described in EP 1 367 166 B1, however, are mechanically complicated and maintenance-intensive.
It is an object of the present invention to provide a device for the guided transport of a card web which guarantees with little effort the trouble-free guidance of the card web even at high speeds and which prevents entrained air from exerting any negative effects on the card web